Thank you for eloquently putting something that I have been struggling to put into words. I really hope that the big instances don’t all end up moving to a whitelist federation model, the ability to have my own instance, with the ability to interact with any community in the fediverse, is what brought me here.
That said, a lot work needs to go into making this platform more resilient against spam bots. The biggest problem I see is that the default instance settings aren’t resistant at all. It seems to me that it shouldn’t even be possible to deploy a lemmy instance with no email verification, no captcha, and open sign-ups, but here we are.
Perhaps some sort of sanity check in lemmy that disables federation in that case might be a good idea. If someone is competent enough to implement their own spam protection beyond those, they’re probably competent enough to fork lemmy and disable said sanity check
Votes are public more of a side effect of the fact that Lemmy is federated, rather than intentionally as something to be publicly visible, I don’t believe you can go find someone’s vote history just from the normal Lemmy ui, but someone could create their own Lemmy/mastodon/kbin version (or just some custom scraper that speaks activity pub and pretends to be one of these) to start collecting vote counts.
Votes being tied to accounts makes it slightly harder to do vote manipulation, but only slightly. It would be as simple as having my server tell the server of the original post that 5000 users that totally exist voted on this post. Of course you could do the same by actually creating 5000 fake accounts on your server, but that’s marginally more work, and also slightly more detectable. There’s a lot of trust in the activity pub protocol.